While Kanno-jigoku Onsen is synonymous with its "13–14°C cold medicinal spring," it was historically only accessible for three months during the summer. This created a significant business challenge, with few guests visiting during the winter.
To solve this, the facility underwent a major evolution in July 2023. Produced by the legendary "Totonoe Oyakata" and "Sauna Shisho," a new world-class sauna was born, transforming the site into a "Mecca" for sauna enthusiasts in Kyushu.

寒の地獄温泉は「13〜14℃の冷たい霊泉」が代名詞だが、霊泉に入れるのは夏の3ヶ月間のみで、冬場は宿泊客も少なく経営的な課題を抱えていた。
「ととのえ親方」と「サウナ師匠」のプロデュースにて、2023年7月サウナが完成。
九州の「サウナの聖地」へと進化した。

Around 2019, during a magazine project to select the "37 Recommended Saunas," Totonoe Oyakata made the unprecedented move of nominating Kanno-jigoku Onsen—despite it having no sauna at the time. He selected it based solely on the extraordinary specs of its "13°C cold medicinal spring."
Praising the spring’s potential as the "best cold plunge in Japan," his endorsement led to a landmark collaboration. To allow guests to enjoy these waters year-round, the first-ever tag-team project between Totonoe Oyakata and Sauna Shisho was launched, bringing a world-class sauna to the site.

2019年頃、ととのえ親方が雑誌の「おすすめサウナ37選」という企画で、サウナがないのにもかかわらず、「水風呂13℃、サウナなし」という異例のスペックで寒の地獄温泉を選出。
この霊泉のポテンシャルを「日本一の水風呂」と絶賛したことで、この霊泉を1年中楽しむために初めての「ととのえ親方」「サウナ師匠」のダブルタッグのサウナが誕生した。

By pairing the 13°C "Cold Hell" spring with a powerful wood-burning sauna, the facility now offers the ultimate "Totonoi" experience. This addition has been a major turning point for the inn: what was once a summer-only ritual has been transformed into a year-round destination, allowing guests to fully embrace the power of the sacred spring in any season.

13℃の冷泉（寒の地獄）に対し、薪ストーブでしっかりと温まるサウナが誕生したことで、最高のととのい体験ができるように。
これまで夏限定だった霊泉入浴が、サウナ誕生をきっかけに1年中楽しめるようになり、宿にとっても大きな転換点となった。